Here is a link to a video of my boost issue. Im also starting to think its waste gate springs. Note, im at full throttle until I see the boost drop to 10 psi, then I let off.

http://www.friendly-online-gamers.net/downloads/BoostDrop.mp4

 

What makes you think its the waste gate?

Once you are making boost and the gate is open it shouldnt fall like that.

Looks like the BOV is opening or something crazy?

 

Up until 18 psi its rock solid. The moment you cross that threshold its done. Im guessing i should remove both gates and inspect them. wonder if one is having trouble? The last non SP cover turbos would drop to 10 p[si, and then bounce 10-13psi and make a shoosh sound when they did that and that sound was in syncronos with the psi readings.

 

Have you tested the gates?

 

No. Haven't tested them and truck has never been turned up over 17 psi by any of the previous owners. If I keep it at 18 and under it pulls like a freight train with no hicups

 

I know someone stated this in your other thread, but it seems like an EBC problem. Start troubleshooting the problem by eliminating the easiest things first.

Try and run the wastegate without the EBC. Attach the bottom port's hose to the top port and leave the bottom port open. This should make boost that exceeds what you run with the EBC. If it still drops, then you can rule out the EBC and any electrical issues like overboost protection failing or the solenoid failing.

Next I would test your BOV. If you still hear the swoosh sound while you are testing the above and the above doesn't help. If you get a sudden drop in air pressure in the manifold, you would have a large enough pressure difference that it opens the BOV, and it could drop 10psi. I don't know about the fluttering of the boost pressure, or why it wouldn't jump back to 20psi. Your car builds boost quick so It should jump back up.

Have you data-logged the problem? Is anything happening in the tune?

 

datalogs look good. and air fuel is spot on. Like i said, under 18 psi truck makes over 700HP, When i set it just to the thrshold i can hear the waste gates changin sound like theyre trying to close. And if I let the throttle out just a bit, it climbs again.

 

I guess try and change springs? If it is the WG making the swoosh sound not the BOV. I would still try the line switching because it is easy. And then address the gates. It shouldn't fall that fast if it is the springs unless some crazy even is happening like a valve getting slammed open and stuck.

 

What is the timing doing on the data logs?

 

Street tune never got es over 12 deg. Holds steady too

 

Not to be a pain but you verified the timing holds steady even over 18psi. I was thinking the street tune may have a boost threshold, or IAT timing retard built in?

 

IATA never go over 150. Tune is set up to start pulling timing after that. On the lightning its all based on Maf tables , load tables and o2 ect. Pcm doesn't take boost into account. I have one more video to load which shows the issue much more pronounced,with the old turbos. Will upload it tonight. I have a box truck that needs breaks today...ughh. honest for the weary